Low socioeconomic status (SES) has a profound influence on physical health outcomes throughout the lifespan. For example, the most common childhood chronic health condition, asthma, is more severe in low SES children. Understanding the reasons why low SES children suffer from worse asthma thus has important public health implications. This proposed project seeks a more thorough understanding of both psychological and biological pathways that could help to explain epidemiological findings linking low SES with increased asthma severity. The focus will be on the effects of SES on stress and biological systems that have been implicated in asthma exacerbations. The specific aims of this proposal include: 1) Examining the dimensions of SES (prestige SES, resource SES, relative SES) that are associated with asthma biological processes, and considering the implications of these associations for our understanding of how SES impacts asthma; 2) Determining which components of stress (stress exposure, stress interpretations, stress reactivity) form psychological pathways between SES and asthma biological processes; and 3) Identifying psychological factors that characterize a subgroup of vulnerable children (low SES) who are resilient (have good asthma profiles). This last aim will entail assessing child characteristics (e.g., control) as well as social network factors as potential buffers of the SES and asthma relationship. We will recruit a sample of 120 children (ages 13-18) with persistent asthma. Children will be interviewed about life stresses and parents interviewed about family SES. Biological processes implicated in asthma, including immune markers (e.g., cytokines) and neuroendocrine hormones (salivary cortisol), as well as asthma outcomes (e.g., pulmonary function) will be assessed. Children will be tested 5 times over a 2-year period to track changes in stress and asthma. The results from this project will allow us to begin developing models of how the larger social environment comes to affect a child's clinical course of asthma.